Voltage transformation apparatus



Dec. 13, 1938. R. H, SULLIVAN v 2,140,094

VOLTAGE TRANSFORMATION APPARATUS Filed July 24,k 1957 I I 74 J/w 48 Il im? Hmmmomo Patented Dec. 13, 1938 UNITED STATES PATENT OFFICE Raymond H. Sullivan, Rochester, N. Y., asslgnor to General Motors Corporation, Detroit, Mich., a. corporation of Delaware Application July 24, 1937, Serial No. 155,496

7 Claims.

out appreciable delay in attaining full amplitude of the vibratory member.

Another object of this invention is to provide an actuating system for a vibratory current switching devicen which tends to reduce contact damage due to sparking.

The above objects are accomplished in a system incorporating a vibratory reed anchored at one end and having its other end free to vibrate by utilizing a set of normally closed contacts, a set of normally open contacts, both of which sets of contacts are controlled by the reed, and providing electromagnetic means including two electromagnet windings for actuatingthe reed,v

one of which windings is connected to a source of direct current through the normally closed contacts and the other of which windings is connected across the normally open contacts, the current flow through the normally closed contacts being interrupted thereby before the normally open contacts short circuit the other winding.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accom panying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

The single figure of the drawing is a schematic circuit diagram of a system embodying a preferred form of the present invention.

With particular reference to the drawing, a resilient reed iii is anchored at one end, such as at I2, and has its other end free to vibrate. Contacts lll and I6 are mounted on opposite sides of the reed near the free end thereof. Cooperating stationary contacts I8 and 20 are mounted in alignment for engagement with thecontacts I4 and I6 respectively. In the normal position of rest of the reed I0, the contacts I4 and I8 and I6 and 20 are disengaged or open. Also near the free end of the reed, a contact 22 is mounted on the same side of the reed as the contact I4 and on the opposite side. of the reed from the contact I 6. A stationary cooperating contact 24 is mounted in alignment for engagement with the contact 22, and these contacts 22 and 24 are engaged or closed when the reed I0 is in the normal position of rest. An electromagnet or electromagnetic means 26 has two windings 28 and 30, which windings are preferably wound in bifllar relation on a common core which is indicated at 32. The core 32 is eccentric to the reed I0 and in magnetic relation thereto.

A battery or source of direct current 34 has one end connected to the reed I0 and its other end connected through a switch 36 to a center tap 38 of a primary winding 40 of a transformer 42. One end of the primary winding 4D is connected to the contact 20, and the other end of the winding 40 is connected to the contact I8. The electromagnet winding 30 is connected across the contacts I6 and 2li. The other electromagnet winding 28 has one end connectedv to the battery 34 through the switch 36 and its other end connected to the contact 24. 'I'he resistance of each of the electromagnet windings is preferably high in comparison to the resistance of the halves of the transformer primary winding; as for example, about 30 ohms has been found to be a satis factory resistance for each of the electromagnet windings as compared to about .06 ohm for each half of the primary winding.

The transformez' 42 has a core 44 and a secondary Winding 46 which is magnetically coupled to the primary winding 40 through the core 44. The secondary winding 46 preferably has a center tap 48 that is connected to an output lead 50 and is preferably grounded at 52. The ends ofA they secondary winding 46 are connected to plates or anodes 54 and 56 of a conventional rectiler tube 58 and to the terminals of a condenser 49. A filament or heater element 6U of the rectier tube 58 is connected across the battery 34. and a switch 62 is preferably included in one lof the leads from the battery 34 to the filament or heater element to effect deenergization of the filament or heater. A cathode element 64 of the rectifier tube 58 is connected to an output lead 66. A choke coil 68, preferably having an iron core 10, is connected in series with the output lead 66. Condensers 'I2 and I4 are connected across the output leads 50 and 66 on opposite sides of the choke coil 68. They output circuit including the rectifier tube 58, choke coil 68 and condensers 'l2 and 14 are merely illustrative of one kind of an output circuit that may be used stood that by utilizing additional contacts the rectification of the secondary voltage could very well be accomplished through the action of the reed and without the rectiiler tube 58. It is also understood that the present invention might very well be embodied in a system which does not include a rectifying means, or one which uses any one of the number of varieties of filters with the rectifying means.

In the operation of the system disclosed, the vibratory reed I0 has anormal position of rest, such as that illustrated in the drawing, in which the contacts I4 and I8 are open, the contacts Il and 20 are open and the contacts 22 and 24 are closed. Upon closing the switch 36, the electromagnet winding 28 is energized by current from the battery or source of direct current 34 through the normally closed contacts 22 and 24. Also, the electromagnet winding 30 is energized by current from the battery or source of direct current 34 which ows through one half of the primary winding 40. The consequent energization of both windings of the electromagnet provides a strong attracting force which moves the free end of resilient reed I0 toward the core 32. At a predetermined point in the movement of the reed l0 toward the core 32 at the contacts 22 and 24 open to effect deenergization of the electromagnet winding 28. Continued movement of the reed Ill toward the core 32 effects engagement of the contacts i6 and 20. The engagement of the contacts i6 and 20 short circuits the electromagnet winding 30 to effect deenergization thereof, although the short circuiting of the electromagnet winding 3l) tends to delay the decay of the flux of the electromagnet while the contacts I6 and 20 are engaged. The deenergization of both of the electromagnet windings 28 and 30 releases the reed l0, so that the resilience thereof carries the free end of the reed away from the core 32, whereupon the contacts 22 and 24 reengage, and thereafter the contacts I4 and I8 engage. Either one or the other of the contacts 22 and 24 are resiliently mounted so as to permit the reed I0 to swing to the left from the position shown in the drawing in order to bring the contact I4 into engagement with the contact I8 after contact 22 has engaged contact 24. During the engagement of the contacts I4 and I8, the reed is stressed in a position away from the core 32, and due to such stress, as well as the reenergization of the electromagnet windings 28 and 30, the above outlined action of the reed is repeated.

During the time that the contacts IS and 20 are closed, one half of the primary winding 40 is energized by current flow from the battery or source of direct current 34 through those contacts. During the time that the contacts I4 and I8 are closed, th other half of the primary winding 40 is energized by current ilow from the battery or source of direct current 34 through those contacts, and by a current flowing in the opposite direction in the primary winding from that which energized the first mentioned half thereof. The alternate energization of the halves of the primary winding 40 in opposite directions during vibratory movement of the reed I0 creates a full wave alternating potential across the secondary winding 46, which secondary voltage value depends upon the characteristics 0f the transformer 42. The resistance of the electromagnet winding 30 s preferably sufficiently high that the current ow through the half of the primary winding that is in series therewith when in the present system. It is, of course, underthe contacts I! and 20 are open is small with respect to the current flow therethrough when those contacts are closed.

From the foregoing description, it will be readily understood that when the reed is stationary, and then the electromagnet windings 28 and 30 are energized by closing the switch 36, the pull or force of the electromagnet 28 on the reed Il) is strong. This strong pull or force is very desirable in starting the reed, to effect quick starting, without the delay of several cycles of reed movement before the reed reaches full amplitude. It is also desirable to have such strong pull when the reed is away from the core 32 and during operation, so that the reed will vibrate uniformly and properly over a wide range of voltages from the source 34, and particularly when the voltage of the source 3411s below normal. It has been found that the delay of the decay of the electromagnet flux resulting from the short circuiting of the electromagnet winding 30 has a very benecial effect in the reduction 'of contact sparking. It will also be understood that the relation, spacing and adjustment of the various contacts in the instant system provides a flexibility of design which permits desirable operation of the reed to be attained. When the contacts are properly adjusted, so that they make and break in the order defined above, practically sparkless operation of the contacts results. The present system therefore prolongs contact life by minimizing sparking at the contacts, as well as by limiting mechanical wear or damage to the contacts; and the system accomplishes these results together with providing a device which starts andv reaches full amplitude very quickly, and operates satisfactorily over a wide range of voltage.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

l. In voltage transformation apparatus, the combination comprising, a resilient vibratory reed anchoredit at one end and having a plurality of contacts mounted thereon near the other end; a plurality of cooperating contacts adapted to engage the contacts on the reed, one pair of said contacts being normally engaged and others of said contacts being normally open; a battery; a transformer having a primary winding, said normally open contacts controlling the current flow from the battery to the primary winding; and an electromagnet having a pair of windings for effecting vibratory movement of the reed, one of the electromagnet windings being connected to the battery through the normally closed contacts, and the other of the electromagnet windings being connected across a pair of the normally open contacts.

2. In voltage transformation apparatus, the combination comprehending, a resilient reed anchored at one end and having its other end free to vibrate; means including a pair of electromagnet windings for effecting vibratory movement of the reed; a transformer; a battery; stationary contacts and movable contacts comprising cooperating pairs, of engageable contacts adapted to intermittently engage during vibratory movement of the reed, at least one pair of said contacts controlling current fiow from the battery to the transformer, one of said electromagnet windings being connected across a pair of said contacts,

and the other electromagnet winding being connected to the battery through one ot the pairs of contacts.

3. In voltage transformation apparatus, the combination comprehending, a resilient reed anchored at one end and having its other end free to vibrate means including a pair of electromagnet windings for effecting vibratory movement of the reed; a transformer having a primary winding; a source of direct current; stationary contacts and movable contacts comprising cooperating pairs of engageable contacts adapted to intermittently engage during vibratory movement of the reed, a pair of said contacts controlling current ow from the source of direct current to the primary windings, one of said electromagnet windings being connected across the last mentioned pair of contacts, the other of said electromagnet windings being connected to the source of direct current through another of said pairs of contacts, the last mentioned pair of contacts being normally engaged,

4. In voltage transformation apparatus, the combination comprehending, a resilient reed anchored at one end and having its other end free to vibrate; means including a pair of electromagnet windings for eifecting vibratory movement of the reed; a transformer having a primary winding having portions connected to a center tap; a source of direct current; stationary contacts and movable contacts comprising cooperating pairs of engageable contacts adapted to inter mittently engage during vibratory movement of the reed, two of said pairs of contacts alternately effecting current flow through said portions of the primary winding, the last mentioned pairs of contacts being normally open, one of the electromagnet windings being connected across one of the last mentioned pairs of contacts, and the other electromagnet winding being connected to the source of direct current through another of said pairs of contacts, the last mentioned pair of contacts being normally closed.

5. In voltage transformation apparatus, lthe combination comprehending, a resilient reed anchored at one end and having its other end free to vibrate: a pair of normally closed contacts, a

pair of normally open contacts. one of the contacts of each of said pairs being mounted on the reed; a battery; electromagnetic means for actuating the reed including two eleetromagnet windings; one of the windings being connected to the battery through the normally closed contacts, and the other winding being connected across the normally open contacts.

6. In voltage transformation apparatus, the combination comprehending, a resilient reed anchored at one end and having its other end free to vibrate; a pair of normally closed contacts, a pair of normally open contacts, one of the contacts of each of said pairs being mounted on the reed; a battery; electromagnetic means for actuating the reed including two electromagnet windings; one of the windings being connected to the battery through the normally closed contacts. and thel other winding being connected across the normally open contacts, said contacts and reed being so arranged that movement of the reed in one direction effects breaking of the normally closed contacts before the normally open contacts engage.

7. In voltage transformation apparatus, the combination comprehending, a resilient reed anchored at one end and having its other end free to vibrate a pair of normally closed contacts, two pairs of normally open contacts, said pairs of normally open contacts being on opposite sides of the reed; a source of direct current; a transformer having a center tapped primary so connected that the halves of the primary are alternately energized from the source of direct current; an electromagnet for effecting vibratory movement of the reed. said electromagnet having a plurality of windings thereon, one of the electromagnet windings being connected to the source of direct current through the normally closed contacts, and another of the eleetromagnet Windings being Aconnected across one pair of normally open contacts, said contacts being so arranged that the last mentioned one pair of normally open contacts short circuits the electromagnet Winding that is connected thereto after the normally closed contacts Open.

RAYMOND H. SULLIVAN. 

